US 2011/0015628 A1 discloses an apparatus for planning an ablation procedure to eliminate a tissue mass in a patient. A tissue mass is identified in the patient, and an image representation of an initial planned target volume encompassing the tissue mass is generated. The initial planned target volume is inscribed in a template ellipsoidal enclosing ablation volume. Minor axes of the template ellipsoidal enclosing ablation volume and the initial planned target volume are scaled upward until they are equal in magnitude to a major axis of the template ellipsoidal enclosing ablation volume, to generate an enclosing sphere that encompasses the scaled planned target volume. In a lookup table a pre-computed ablation solution having a minimum number of spherical ablation regions that cover the enclosing sphere is identified, and a graphical representation of the identified pre-computed ablation solution overlaid on the sphere is output to a user.